<script setup lang="ts">
import { computed, ref, watch } from 'vue'

// 定义水果对象的类型
interface Fruit {
  id: number
  icon: string
  isChecked: boolean
  num: number
  price: number
}

const ListKey = 'cartList'

// 水果列表
const res = localStorage.getItem(ListKey)
let list: Fruit[] = []
// 如果为空，设置初始值
if (res) {
  list = JSON.parse(res)
} else {
  list = [
  {
    id: 1,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/ll.png',
    isChecked: true,
    num: 2,
    price: 6,
  },
  {
    id: 2,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/smt.png',
    isChecked: false,
    num: 7,
    price: 20,
  },
  {
    id: 3,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/tg.png',
    isChecked: false,
    num: 3,
    price: 40,
  },
  {
    id: 4,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/xg.png',
    isChecked: false,
    num: 10,
    price: 3,
  },
  {
    id: 5,
    icon: 'https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/yl.png',
    isChecked: false,
    num: 20,
    price: 34,
  },
]
}
const fruitList = ref<Fruit[]>(list) 

// 侦听器 同步保存数据到 LocalStorage
watch(fruitList, () => {
  localStorage.setItem(ListKey, JSON.stringify(fruitList.value))
}, { deep: true })

// 根据 id 删除数据
const removeItemById = (id: number) => {
  fruitList.value = fruitList.value.filter(item => item.id != id)
}

// 根据 id 增加
const addById = (id: number) => {
  const good = fruitList.value.find(item => item.id === id)
  good!.num++
}

// 根据 id 减少
const subById = (id: number) => {
  const good = fruitList.value.find(item => item.id === id)
  if (good!.num > 1) good!.num--
}

// 全选 计算属性
// 是否全部选中需要根据每一项的选中状态计算而来
const isCheckedAll = computed({
  get() {
    return fruitList.value.every((v) => v.isChecked)
  },

  // 赋值
  // v-model="isCheckedAll"绑定给了 checkbox
  // 点击全选 checkbox 的时候回传给计算属性赋值
  set(value) {
    // 数组每一项的选中状态都改为和全选的状态一致即可
    fruitList.value.forEach(v => v.isChecked = value)
  }
})

// 总个数
const totalCount = computed(() => {
  return fruitList.value.filter(v => v.isChecked).reduce((prev, cur) => {return prev + cur.num}, 0)
})

// 总价格
const totalPrice = computed(() => {
  return fruitList.value.filter(v => v.isChecked).reduce((prev, cur) => {return prev + cur.num*cur.price}, 0)
})
</script>

<template>
  <div class="app-container" id="app">
    <!-- 顶部banner -->
    <div class="banner-box"><img src="https://hongm-1312445828.cos.ap-nanjing.myqcloud.com/sg_top.png" alt="" /></div>
    <!-- 面包屑 -->
    <div class="breadcrumb">
      <span>🏠</span>
      /
      <span>购物车</span>
    </div>
    <!-- 购物车主体 -->
    <div v-if="fruitList.length > 0" class="main">
      <div class="table">
        <!-- 头部 -->
        <div class="thead">
          <div class="tr">
            <div class="th">选中</div>
            <div class="th th-pic">图片</div>
            <div class="th">单价</div>
            <div class="th num-th">个数</div>
            <div class="th">小计</div>
            <div class="th">操作</div>
          </div>
        </div>
        <!-- 身体 -->
        <div class="tbody">
          <div v-for="item in fruitList" :key="item.id" class="tr active">
            <div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
            <div class="td"><img :src="item.icon" alt="" /></div>
            <div class="td">{{ item.price }}</div>
            <div class="td">
              <div class="my-input-number">
                <button class="decrease" @click="subById(item.id)"> - </button>
                <span class="my-input__inner">{{ item.num }}</span>
                <button class="increase" @click="addById(item.id)"> + </button>
              </div>
            </div>
            <div class="td">{{ item.price*item.num }}</div>
            <div class="td"><button @click="removeItemById(item.id)">删除</button></div>
          </div>
        </div>
      </div>
      <!-- 底部 -->
      <div class="bottom">
        <!-- 全选 -->
        <label class="check-all">
          <input v-model="isCheckedAll" type="checkbox" />
          全选
        </label>
        <div class="right-box">
          <!-- 所有商品总价 -->
          <span class="price-box">总价&nbsp;&nbsp;:&nbsp;&nbsp;¥&nbsp;<span class="price">{{ totalPrice }}</span></span>
          <!-- 结算按钮 -->
          <button class="pay">结算( {{ totalCount }} )</button>
        </div>
      </div>
    </div>
    <!-- 空车 -->
    <div v-else class="empty">🛒空空如也</div>
  </div>
</template>

<style scoped>
@import './style/inputnumber.css';
@import './style/index.css';
</style>